A toll-free number is a telephone number in which the cost of the call is charged to the called party rather than to the calling party. In countries that follow the North American Numbering Plan (NANP), telephone numbers are of the form NPA-NXX-YYYY, where NPA is the numbering plan area code, roughly corresponding to a particular geographical area, and NXX is the exchange, which identifies a physical switching facility, called a central office (CO). The remaining digits, YYYY, identify a line card within the CO. When a CO detects that a subscriber whom that CO serves is attempting to place a call to called party telephone number, the values of NPA and NXX of the called party number are used by a switch to determine how to route a call.
A toll-free number, however, may have an “8XX” area code (e.g., 800, 877, 866, etc.), that does not correspond to any geographical location of the called party, and thus cannot be used by itself to determine the destination of the call or how it should be routed. For this reason, switches in conventional telecommunications networks that provide toll free service must send a query to a toll-free database to determine the true destination of the toll-free called party. A query to a toll-free database is herein referred to as a “toll-free query.”A toll-free query typically includes the toll-free number, and the response to the toll-free query typically includes the directory number to which the toll-free number is mapped. For example, Tekelec, Incorporated provides a toll-free number “1-800-TEKELEC” (1-800-835-3532) for sales inquiries. This toll-free number may be mapped to a local directory number for Tekelec corporate world headquarters in Morrisville, N.C., which is 919-460-5500. Thus, a toll-free query for 800-835-3532 would return the directory number 919-460-5500.
Businesses often use a toll-free number as the primary telephone number for callers to use, because the same toll-free number may be used by a caller regardless of the geographical location of the caller. The savings to the business from using the same toll-free number in advertisements around the country, continent, or world, on company business cards and letterhead, and so on, may outweigh the additional expense incurred by the business of paying for the calls. A toll-free number that is very easy for customers or potential customers to remember, as in the 1-800-TEKELEC example, above, may even increase that business organization's sales, help it achieve high name recognition, or provide some other tangible or intangible benefit.
However, business entities or organizations that have a large or dispersed physical presence in the form of branch offices, service centers, or restaurants in different geographic locations, for example, may desire that a call made to the organization be directed to whichever branch office is geographically closest to the calling party. A fictional take-out pizza restaurant chain having stores in multiple geographic locations, for example, may desire that calls to its toll-free number, e.g., 1-800-GO-PIZZA (1-800-467-4992), be routed to the pizza restaurant closest to the geographic location of the calling party. In order to do this, the toll-free query must provide location information for the calling party, and the toll-free database must be able to use this calling party location information to select the appropriate directory number.
The ability to consider the location of the calling party as part of the process of performing a number translation is herein referred to as calling-party-location-sensitive called party number translation, which may be abbreviated to “location-sensitive called party number translation”, or simply “location-sensitive number translation”, for short.
In conventional systems, however, calling party location information may be unavailable or indeterminate. For example, the toll-free query issued by a switch may include the toll-free called party number, but no calling party information. Even if the toll-free query includes calling party information, that calling party information may not indicate the geographic location of the calling party, such as where the calling party number is a mobile subscriber number, in which case the mobile subscriber may be calling from anywhere within the cellular network. Even if the toll-free query includes information that does give some indication of the location of the calling party, conventional toll-free databases may not support calling party information as an input parameter to a toll-free query. The same problems apply to other number translation services that are not location-sensitive.
Accordingly, in light of these disadvantages associated with conventional approaches to providing called-party number translation in a telecommunications network, there exists a need for improved systems and methods for providing location-sensitive called-party number translation in a telecommunications network.